Cylinder detector spark plug



' June 14, 1938. G HANT OP ULOS 2,120,804

CYLINDER DETECTOR SPARK PLUG Filed Oct. 26, 1957 F 1 H 2 I7 ,9

INVENTOR.

BY George #007 'apou/as ATTORNEY.

Patented June 14, 1938 UNITED STATES PATENT, OFFICE 2 Claims.

The purpose of this invention is to provide means in combination with aspark plug for readily detecting the operation of a cylinder upon whichthe spark plug is used, in which the device is adapted to close acircuitfor operating a signal on the instrument board or at a remotepoint. p

The invention is a spark plug having a passage therethroughcommunicating with the interior of the cylinder, and also communicatingwith an auxiliary circuit closing device forming part of the spark plug.

The invention is an improvement over the device ofv my prior PatentNumber 2,096,803, in that the circuit closing device is incorporated ina spark plug, thereby eliminating the necessity of providing anadditional opening in the cylinder, and, at the same time, making thedevice adapted to be sold and installed in combination with the sparkplug and forming a complete unit.

The object of this invention is, therefore, to provide means in a sparkplug for closing a circuit by the pressure of a cylinder upon which thespark plug may be installed so that the circuit may operate a signal ata remote point.

Another object is to provide means for incorporating a circuit closingdevice in a spark plug without increasing the size of the plug.

Another object is to provide means for incorporating a circuit closingdevice in a spark plug without interfering with the eiiiciency of theplug.

A further object is to provide pressure operated circuit closing means,in combination with a spark plug, which may or may not be used asdesired.

And a still further object is to provide pressure controlled circuitclosing means in a spark plug without materially increasing the cost ofthe construction of the plug.

With these ends in view the invention embodies a spark plug having apoint in a porcelain member mounted in a jacket, with a passage throughthe wall of the jacket, and a circuit closing device communicating withsaid passage and mounted upon said plug.

45 Other features and advantages of the invention will appear from thefollowing description taken in connection with the drawing, wherein:

Figure 1 is a cross section through a spark plug showing the contactdevice extending upward 50 from the upper end thereof.

Figure 2 is a plan view of the device shown in Figure 1, showing analternate design in which the contact device extends outward at an angleto the spark plug instead of extending radially there- 5 from.

Figure 3 is a sectional plan on line 33 of Fi ure 1.

Figure 4 is a view, similar to that shown in Figure 1, showing analternate design in which the contact device is incorporated in the headof the spark plug.

Figure 5 is a sectional plan on line 5-5 of Figure 4, showing thecontact operating mechanism.

Figure 6 is a sectional plan on line 66 show- 10 ing the opening in thespark plug, and also having part broken away showing the opening througha nut in the upper end of the spark plug.

In the drawing the device is shown as it may be made, wherein numeral iindicates the jacket 15 of the spark plug, numeral 2, the porcelainmember in the center thereof, and numeral 3, an auxiliary cylinderforming the contact device.

The spark plug I may be made as shown in Figure 1, or as shown in Figure4, however, in 20 the design shown in Figure 1, the porcelain 2 issecured in the jacket by a nut 4, and the contact extending through thespark plug is formed by a rod 5, which extends downward to a point 6adjacent a point i which extends downward from 25 the lower end of thejacket I. The lower portion of the jacket I is threaded, as shown at thepoint 8, and these threads correspond with the threads of spark plugsnow in use so that the spark plug may be screwed into the regular sparkplug open- 30 ing. The lower portion of the jacket I is provided with anopening 9 which extends upward to a. circumferential recess l0, and arelatively small opening ll extends upward from the recess I0 to aprojection I2 extending upward from the upper end of the jacket, and theprojection I2 is provided with a threaded portion l3 upon which" thecylinder 3 may be screwed as shown.

The cylinder 3 is provided with a piston M, having piston rings l5 atone end and a stem I6 extending from the opposite end and also throughthe upper end ll of the cylinder. A spring l8 may be provided around thestem Hi to resiliently hold the piston M downward. At the upper end ofthe cylinder is a cap l9 having a contact point 20 therein, and thecontact point extends through the cap forming a threaded stem or screwto which a wire may be attached for completing a circuit to a remotepoint, the opposite terminal at both ends being grounded. The cap I9 ismade of insulating material, thereby insulating the point 20 from theground. It will be noted that, as pressure in the cylinder increases, itwill be transmitted through the openings 9, III and II to the cylinder3, and this pressure will force the piston l4 upward and the piston willforce the contact point I6 against the point 20. The cylinder wall maybe provided with air openings 21 above the piston to equalize thepressure.

In the design shown in Figures 4, 5 and 6, the device is incorporated inthe head of the spark plug which is formed with a casing 22 having aporcelain 23 similar to the porcelain 2, and this is provided with aninner rod 24 extending downward to a point 25 adjacent to another point26 similar to the point 1. In this design the jacket is provided with anopening 21 extending upward through a passage 28, and in the upper endof the jacket is a nut 29 having a passage 30 therein which opens into atubular member 3|, which is formed of relatively thin material andadapted to expand as the pressure therein increases. The opposite end ofthe member 3| is connected by a link 32 to a contact point 33 formed atthe end of a spring 34, and extending into an opening 35 in a porcelainmember 36, and it will be noted that, as the member 3| expanw, the link32 will draw the point 33 inward, causing it to contact the inner end ofa screw 31 extending into the opposite end of the porcelain, andconnected by a member 38 to a screw 39 which extends through the wall ofa cap 40, providing means for attaching a contact wire similar to thescrew 2| of the design shown in Figure 1. The porcelain cylinder 36 ismounted upon the porcelain 23 by a clamp 4! held by a screw 42, and theinner end of the spring 34 is also held on the screw by a nut 43 asshown. The opposite side of the clamp 45 is provided with a strap 44which extends around the porcelain cylinder 36 as shown. The cap 40 ismounted upon the porcelain 23, and this may be of insulating material,insulating the screw 39 from the jacket of the spark plug. In thisdesign the porcelain 23 is held in the spark plug by an inner nut 45,similar to the nut 4 in the design shown in Figure 1, and the threads 46at the lower end are similar to the threads 8, so that this spark plugmay also be used in the usual spark plug opening.

It will be understood that other changes may be made without departingfrom the spirit of the invention. One of which changes may be in the useoi this device in combination with a spark plug of any other type ordesign, another may be in the use of other means for providing an openpassage through the spark plug, and still another may be in the use ofother means for incorporating a contact device in the head of a sparkplug.

The construction will be readily understood from the foregoingdescription. In use the device may be provided as shown and described,and it will be noted that it may readily be screwed into the usual sparkplug opening, and the contact screw at the upper end may be connected bya wire to a small light on the instrument board, or at any point, and,with the other terminal grounded through suitable current supplyingmeans, the light will light when the cylinder explodes, or when thepressure reaches a predetermined amount; or it will not light if thepressure does not reach this amount, or if the cylinder does not fire.The device, therefore, makes it possible to readily indicate theperformance of each cylinder of an internal combustion engine, so thatthe operator of the vehicle in which the device is installed may readilydetermine whether or not every cylinder is firing, and Whether or notthe pressure in each cylinder is what it should be In the device shownin Figure 4, the entire upper part of the plug is assembled as a unitand may be removed from the jacket by unscrewing the nut 29, and thismay be replaced with the points assuming their original positions.

Having thus fully described the invention, what I claim as new, anddesire to secure by Letters Patent, is:

i. In a spark plug of the type having a metallic shell, with aninsulating member extending through the central part thereof, and having

